SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '601a2126afc9671105304a4e1c966a615432ea01074d7eb972d8013415ea7cf3' 
  AND token = 'pQXVM1+B4taZrmKw3doIrN2RsRUP5zPswjdHR0t1RmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}